U.S. patent number 4,753,616 [Application Number 07/047,104] was granted by the patent office on 1988-06-28 for contact element for an electrical plug connector.
This patent grant is currently assigned to Otto Dunkel GmbH, Fabrik fur Elektrotechnische Gerate. Invention is credited to Paul-Rainer Molitor.
United States Patent |
4,753,616 |
Molitor |
June 28, 1988 |
Contact element for an electrical plug connector
Abstract
The contact element for an electrical plug connector has a
plurality of contact springs disposed side by side, each such
spring being a segment of a contact spring wire, one end of which
is attached to a bearing piece. Each such spring has, in its middle
region, a contact locus which provides contact with a cooperating
contact piece. In order to substantially simplify the structure
from a manufacturing engineering standpoint, a single structural
unit is formed from a first metal strip which forms the bearing
piece, a plurality of spacing members connected to the bearing
piece and extending parallel to each other, and a second metal
strip parallel to the first, which second strip forms the support
piece. In the neighborhood of the bearing piece and support piece,
the spacing members undergo a bending away from the common plane of
the bearing piece and the support piece and toward the front side
of the contact element, such that the middle extent of the spacing
members is disposed such that any two given successive spacing
members laterally define a flat chamber. In this chamber a
plurality of parallel contact springs are disposed side by
side.
Inventors: |
Molitor; Paul-Rainer
(Muhldorf/Inn, DE) |
Assignee: |
Otto Dunkel GmbH, Fabrik fur
Elektrotechnische Gerate (Muhldorf/Inn, DE)
|
Family
ID: |
6300630 |
Appl.
No.: |
07/047,104 |
Filed: |
May 8, 1987 |
Foreign Application Priority Data
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May 12, 1986 [DE] |
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3615915 |
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Current U.S.
Class: |
439/787; 439/843;
439/825; 439/851 |
Current CPC
Class: |
H01R
13/187 (20130101); H01R 13/17 (20130101) |
Current International
Class: |
H01R
13/187 (20060101); H01R 13/15 (20060101); H01R
011/09 () |
Field of
Search: |
;439/884,885,891,786,787,816,825,826,827,834,839,842,843,847,851,852,856,857,858 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0092471 |
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Oct 1983 |
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EP |
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1590124 |
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Jul 1966 |
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DE |
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2558003 |
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Jun 1977 |
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DE |
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1388666 |
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Jan 1965 |
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FR |
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1288757 |
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Sep 1972 |
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GB |
|
Primary Examiner: Pirlot; David
Attorney, Agent or Firm: Holman & Stern
Claims
I claim:
1. A contact element for an electrical plug connector,
comprising:
an assembly including a first metal strip comprising: a bearing
piece, said first metal strip extending in a longitudinal
direction; a plurality of spacing members connected to said bearing
piece and extending in a generally parallel direction to one
another, and a second metal strip extending in a generally parallel
direction to said first metal strip, said second metal strip
comprising a support piece;
in the vicinity of said bearing piece and said support piece, said
spacing members being bent away from a common plane of said bearing
piece and said support piece and toward a front side of said
assembly, such that a middle extent of said spacing members is
disposed such that any given two successive spacing members
laterally define a flat chamber therebetween; at least one contact
spring being disposed in said flat chamber;
a plurality of contact springs disposed in side by side
relationship, each of said springs comprising a segment of a
contact spring wire one end of which is attached to said bearing
piece, and each having, in a middle region thereof, a contact locus
adapted for contact with a cooperating contact piece;
said contact springs extending in a direction which is generally
perpendicular to said longitudinal direction of said bearing piece
and said support piece.
2. A contact element according to claim 1, wherein said two metal
strips forming said bearing piece and said support piece,
respectively, are bent in an essentially cylindrical shape around
an axis perpendicular to a longitudinal direction of said strips
and at a predetermined radial distance from them.
3. A contact element according to claim 1, wherein said axis,
around which the two said metal strips are bent to form said
assembly, is facing a front side of the assembly; and a contact
plug structure having a plug body on which said assembly is
mounted; said spacing members abutting against said plug body.
4. A contact element according to claim 1, wherein said assembly,
comprised of said two metal strips and said spacing members, is
stamped out of a single sheet of contact metal.
5. A contact element according to claim 4, wherein said contact
springs are radially curved rearwardly, in their middle region
between said bearing piece and said support piece, in order to
provide good electrical contact.
6. A contact element according to claim 1, wherein in order to
provide good electrical contact, said contact springs are disposed
at an angular disposition to said longitudinal direction of extent
of said bearing piece and said support piece, the angular
disposition being in a middle region of said contact springs
between said bearing piece and said support piece;
said spacing members also being disposed at an angle so as to be
generally parallel to said contact springs.
7. A contact element according to claim 6, wherein said contact
springs are fixedly joined to said bearing piece and to said
support piece.
8. A contact element according to claim 1, wherein said axis,
around which said two metal strips for forming a contact socket
structure are bent, is adjacent a rear side of said assembly;
further comprising a socket body housing said assembly;
said spacing members being in abutment with said socket body.
9. A contact element according to claim 8, wherein said socket body
comprises a turned sleeve for accommodating said contact
socket.
10. A contact element according to claim 8, comprising two units,
each comprised of a bearing piece, a support piece, and a spacing
member, joined in the axial direction to form a double unit which
can be used as a double socket; said contact springs, which extend
in a direction which is generally parallel to said axial direction
through the entire structure comprised of both units, are joined to
an associated combined common said bearing piece in a central
region of the double socket.
11. A contact element according to claim 8, wherein said socket
body has a centrally projecting rod element at an end of said
socket body which is directed toward an electrical connecting
piece; said rod element together with said socket body defining a
ring-shaped groove into which said contact socket structure can be
inserted; said contact socket structure being held in place at said
electrical connecting piece by a radially inwardly directed
deformation of said socket body.
12. A contact element according to claim 8, wherein said socket
body comprises a cylindrical sleeve formed from sheet metal, with
said contact socket being adapted to be pushed into said
sleeve.
13. A contact element according to claim 12, wherein said socket
body has a radially directed guide edge which extends in front of a
cylindrically formed said support piece, against which piece free
ends of said contact springs are in abutting contact.
14. A contact element according to claim 1, further comprising a
socket housing for forming a flat contact spring socket, said
socket housing having a flat recess into which said two metal
strips with said spacing members and radially curved contact
springs are inserted, with said metal strip forming said bearing
piece being inserted first, said metal strips being affixed to said
housing; in assembled condition, said spacing members abutting one
of two flat walls of said recess, and said contact springs
extending out into said recess, and said metal strip which forms
said support piece being disposed near an external opening of said
recess.
15. A contact element according to claim 14, wherein, to protect
said free ends of contact springs from being contacted by and being
damaged by an opposite contact, said metal strip forming said
support piece having an extension edge which extends in a plane of
a main extent of said spacing members.
16. A contact element according to claim 14, wherein a holding slot
adjoins said flat recess;
said metal strip which forms said bearing piece being affixed in
said slot.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a contact element for an
electrical plug connector.
In a known contact socket element of this type which can be
manufactured by automatic means (West German Pat. No. 15 90 124),
the bearing piece which bears the contact springs is comprised of a
sleeve, and the contact springs extend at an angle to the axis of
the sleeve and have bent-around ends which are attached to the edge
of the sleeve. Since the contact springs have a configuration
including an element corresponding to a set of generatrices of a
hyperboloid of revolution, they have the minimum mutual transverse
separation in approximately their middle region, considered in an
axial cross section through the sleeve with the contact springs
mounted on it. Accordingly, these are the locations of the contact
loci where the contact pin or plug comes into electrically
conducting contact with the contact springs.
It has proven to be disadvantageous with these known contact spring
sockets that one must have a relatively large sleeve to mount the
contact springs and hold them in place, in which sleeve only a few
contact springs can be inserted, sequentially, followed by the
relatively costly effort of attachment of their end faces. These
problems are particularly acute in the case where one attempts
miniaturization of contact spring sockets, having diameters less
than 1 mm.
In a contact element in the form of a contact spring socket or
spring-loaded pin or plug, according to an older unpublished West
German Patent Application No. P 36 08 276.7, the contact springs
are connected by metallic conducting means on one of their ends to
form a mat-like contact spring unit, the springs running mutually
perpendicularly, and are given a radially curved configuration,
following which this unit is rolled into a cylindrical shape which
enables attachment to a separate support piece. This eliminates the
problem arising in the manufacture of previously known contact
elements as seen in West German Pat. No. 25 58 003 wherein a
mat-like contact spring unit has contact spring wire bent into a
wave shape, wherein the contact spring wire segments, which run
parallel to each other, are interconnected by arcuate conductor
segments. Because in practice there is a minimum practicable radius
of curvature for the curved connecting segments, there is in
practice a minimum mutual separation distance of the contact spring
wire segments. Further, it has been found difficult to manipulate
the contact spring mat of the type described in West German Pat.
No. 25 58 003 because of its inherent flexibility and its
elasticity. In particular, distortion results from the fact that
the arcuate segments resist bending around an axis parallel to the
contact spring wire segments.
The underlying problem of the present invention is to devise a
contact element of the type referred to initially supra, which
element has a relatively simple structure, can be inexpensively
manufactured, and is of compact size, preferably for use with plug
connectors, yet has high current carrying capacity and low required
plug insertion forces.
SUMMARY OF THE INVENTION
The present inventive contact spring socket solves the foregoing
problems and can be manufactured from wire-like metal strips to
form the bearing piece and support piece, and wire-like material
can also be employed to form the spacing members which are formed
and combined to create flat open rectangular regions referred to
hereinafter as flat chambers. It is particularly advantageous if
the two said metal strips and the spacing members are together
stamped as a single structural unit from a sheet of contact
metal.
It is advantageous to employ two metal strips of very thin sheet
metal, joined by formed spacing members, such that the two thin
metal strips serve as the bearing piece and support piece,
respectively. As a result, a relatively simple, convenient,
completely automatic means can be used to apply and affix the
contact springs while the strips are still in a flat configuration.
The contact element having the characteristic inventive structure
forms the critical component in manufacturing linear or cylindrical
contact sockets and plugs, wherein the contact is established and
maintained without significant problems and with minimal contact
resistance, while at the same time the required plug insertion
force is relatively low. The inventive contact element is
particularly suitable for multiple plug connectors.
It has proven advantageous in applications of contact elements to
form a contact spring plug or a contact spring socket if the two
metal strips forming the bearing piece and support piece,
respectively, are bent into an essentially cylindrical shape around
an axis perpendicular to the longitudinal direction of extent of
the respective metal strips and at a predetermined distance from
them. By simple bending about the axis, the contact element can
then be given the desired cylindrical (plug or socket) form. The
substantial advantage affored is that a socket body or a plug body
can be used in conjunction with a unit comprised of the bearing
piece and support piece, to which unit the contact springs are
attached, such that the diameter of the body is adjusted to the
diameter in the cylindrical contact pin structure or contact socket
structure of the spacing members which are bent outward from the
level of the support piece and bearing piece, after the unit
comprised of the support piece and bearing piece has been bent into
a cylindrical shape. A further advantage is that the cylindrical
contact pin structure or contact socket structure can be pushed,
respectively, into the socket body or onto the plug body, with
elastic deformation of the spacing members. In this way,
particularly good passage of current from the contact springs to
the socket body is ensured.
In one embodiment, it has been found particularly advantageous if
the contact springs are radially curved toward the rear out of the
plane of the original flat strips, in their middle region between
the bearing piece and the support piece, in order to provide good
contact.
This curvature may be dispensed with if the contact springs are
disposed at an angle to the longitudinal extent of the bearing
piece and support piece, said angular disposition being in the
middle region of the contact springs between the bearing piece and
support piece, and if the associated spacing members are disposed
so as to be generally parallel to said contact springs. Here the
disposition of the contact springs ensures that when the metal
strips forming the bearing piece and support piece are bent into
the cylindrical shape, the contact springs assume a position
corresponding to that in the known contact spring sockets mentioned
supra wherein compact sleeves are started with for affixing the
contact springs to. In this connection, it is advantageous if the
contact springs are firmly joined not only to the bearing piece but
also to the support piece. With this embodiment the spring force
depends on the size and number of the spacing members between the
bearing piece and support piece, because these determine the
distance between the support pieces which hold the ends of the
contact springs.
In forming contact spring sockets, it has been found advantageous
if the axis, around which the two metal bearing strips for forming
a contact socket structure are bent, is facing the rear side of the
contact element; and if the contact socket structure is provided
with a socket body which houses it, such that the spacing members
abut the socket body. This socket body may be comprised of a
cylindrical sleeve formed from sheet metal, with the contact socket
structure being capable of being pushed into said sleeve. With this
embodiment, an additional radial structure may optionally be
provided on the socket body, for attaching of the contact socket
structure thereto.
In another embodiment, a socket body in the form of a turned
cylinder is used to house the contact socket structure.
The features of the present invention also provide in another
embodiment an advantageous means of broadening the range of
possible applications of the inventive contact element to encompass
the manufacture of double sockets.
The inventive contact element can also be advantageously used in
forming spring-loaded plugs wherein an axis, around which the two
metal bearing strips are bent to form a contact plug structure, is
facing the front side of the contact element, and wherein the
contact plug structure is provided with a plug body on which it is
mounted and against which the spacing members abut. Here too, with
a socket structure, the spacing members which elastically abut the
exterior side of the plug body provide for relatively problem-free
passage of current from the contact element to the plug body.
In the manufacture of cylindrical contact spring sockets or of
spring-loaded plugs, it has proven advantageous if the socket body
or plug body has a radially directed guide edge which extends over
or in front of the cylindrically formed support piece against which
piece the free ends of the contact springs abut.
In the formation of a contact spring from flat, elongated members,
with the aid of the inventive contact element, a socket housing is
advantageously employed which has a flat recess into which the two
metal strips with the spacing members and the radially curved
contact springs are inserted, with the metal strip forming the
bearing piece being inserted first, and to which housing said metal
strips are affixed, such that the spacing members abut one of the
two flat walls of said recess, the contact springs extending out
into the recess, and the metal strip which forms the support piece
being disposed near the external opening of the recess.
In order to ensure that the free ends of the contact springs are
not contacted on their end faces by, and damaged by, the opposite
contact when the latter is inserted into the contact spring socket
or over the contact spring plug, it has proven advantageous to
provide the metal strip forming the support piece with an extension
edge which extends in the plane of the main extent of the spacing
members.
Additional details, advantages, and features of the present
invention will be seen from the following description and from the
drawings. Express reference to the drawings is made herein for the
purpose of formal disclosure of all details not described in the
text.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a segment of a contact element;
FIG. 2 is a cross sectional view through line II--II of the contact
element of FIG. 1;
FIG. 3 is a plan view of a variant embodiment of the contact
element of FIG. 1;
FIG. 4 is a longitudinal cross section through a linear contact
spring socket containing the illustrated contact element;
FIG. 5 is a longitudinal cross sectional view of two variant
embodiments of a contact spring socket containing the illustrated
contact element;
FIG. 6 is a longitudinal cross section through a double contact
spring socket;
FIG. 7 is a cross section through a contact element used in the
double contact spring socket of FIG. 6; and
FIG. 8 is a longitudinal cross section through a plug which employs
the illustrated contact element.
DETAILED DESCRIPTION OF THE INVENTION
It is seen from the drawings that the contact element 1 for
electrical plug connectors comprises a plurality of contact springs
2 disposed side by side, each such spring being a segment of a
contact spring wire, one end of each segment (the lower end in FIG.
1) being attached to a bearing piece 3 by means of soldering or
welding, preferably by laser welding. In a middle region 4, the
springs 2 have a contact locus which provides contact with a
cooperating contact piece (not shown), which contact locus will be
described further infra. Parallel to the bearing piece 3 formed by
a first metal strip is a support piece 5 formed by a second metal
strip at a predetermined distance from the first. Support piece 5
and bearing piece 3 are connected as a structural unit by spacing
members 6. The unit comprised of the metal strips 3 and 5 and the
spacing members 6 is preferably formed by being stamped out of a
sheet of contact metal.
As seen from FIG. 2, the spacing members 6 are bent forward
(upward, from the plane of FIG. 1) out of the plane of the bearing
piece 3 and support piece 5, said bending occurring in the
neighborhood of strips 3 and 5. The spacing members 6 are
configured such that any two successive spacing members 6 laterally
delimit a region therebetween along the strips 3, 5, this region
being referred to hereafter as a flat chamber. In each of the
exemplary embodiments illustrated in FIGS. 1 and 3, groups of five
contact springs 2 are disposed side by side in a planar disposition
between any two adjacent pairs of spacing members 6, which springs
are perpendicular to the longitudinal extent of bearing piece 3 and
support piece 5. This perpendicularity is retained even if the
contact springs 2 are given a radial curvature (by any known
process, such as stamping) toward the rear, in their middle regions
4 (between the bearing piece 3 and the support piece 5), as seen in
FIG. 4. The terms "front" and "rear" as used herein refer to
directions taken from FIG. 1.
As illustrated in FIGS. 5 to 8, the two metal strips which form the
bearing piece 3 and the support piece 5 are bent into an
essentially cylindrical shape, about an axis running perpendicular
thereto and at a predetermined radial distance therefrom. In the
case of FIGS. 5-7, the axis A--A about which the two metal strips
3,5 are bent is facing the rear side 22 (as viewed originally in
FIGS. 1 and 2) of the bearing piece 3 and support piece 5, so that
a cylindrical contact socket is formed from the original contact
element. The bending axis coincides with the axis A--A of the
contact socket. In the contact sockets of FIGS. 5 and 6, a
generally cylindrical socket body 7 is provided which contains the
contact element. The spacing members 6 are braced against the body
7.
In the embodiment illustrated on the right half of FIG. 5, the
socket body 7 is comprised of a sleeve formed into a cylindrical
shape from a sheet of metal. The contact socket structure formed by
a cylindrically bent segment of the contact element 1 can be pushed
into the body 7. The spacing members 6 are then lodged elastically
against the socket body 7, which provides relatively problem-free
conduction of current between the body 7 and a contact socket
structure.
In the embodiment according to FIG. 6, two units, each comprised of
a bearing piece 3, a support piece 5, and spacing members 5,6 are
joined in the axial direction to form a double unit which can be
used as a double socket. In this case, the contact springs 2 which
run lengthwise in the direction of the axis A--A through the entire
structure are joined to the associated single, common, bearing
piece 3 in the central region 8 of the double socket. In the region
of the two support pieces 5,5 of the double socket, the free ends
of the contact springs 2 rest against the support pieces 5,5.
In the double socket of FIG. 6 and in the simple contact spring
socket of FIG. 5 (shown in the left half), the socket body 7 is
comprised of a turned cylindrical piece for accommodating the
contact socket structure. The socket body 7 of FIG. 5 (shown in the
right half thereof) has a centrally projecting rod element 10 at
the lower end of said body 7, which lower end is nearer the
electrical connecting piece 9. The rod element 10 together with the
socket body 7 defines a ring-shaped groove into which the bearing
piece end, formed by bearing piece 3, of the contact socket
structure can be inserted. The bearing piece 3, with the ends of
the contact springs 2 of the contact socket structure, is held in
place at the electrical connecting piece 9 by means of a radially
inwardly directed deformation 23 of the socket body 7.
FIG. 3 illustrates a variant embodiment of a contact element 1'.
Here the contact springs 2', in their middle region 4' between the
bearing piece 3' and the support piece 5', are disposed at an angle
to the longitudinal direction of the bearing piece and the support
piece, in order to improve electrical contact. The associated
spacing members 6' are parallel to the contact springs. If this
contact element 1' is formed into a cylindrical shape, the
configuration of the contact springs 2' corresponds to a set of
generatrices of a hyperboloid of revolution. Accordingly, the
contact locus is disposed in the middle region 4', with no
projecting curvature. Electrical contact with the contact springs
is made at the contact locus by the contact plug or pin. With this
embodiment, the contact springs 2' may be affixed to not only the
bearing piece 3' but the support piece 5' as well (in a single
contact socket structure).
FIG. 8 illustrates a connecting plug with a plug body 11 and a
contact plug structure formed by bending the contact element 1 into
a cylindrical shape. In this case the axis around which the two
metal strips 3 and 5 are bent is facing the front side of the
contact element 1. Accordingly, the spacing members 6 are disposed
on the side facing the plug body 11, namely in such a manner that
the members 6 are braced against the body 11, thereby providing
relatively problem-free passage of current between the contact
element 1 (which has been formed into a contact plug structure) and
the electrical connecting piece 9 of the plug body 11.
FIG. 4 illustrates how a contact element 1 according to FIGS. 1 and
2 can be used without forming it into the cylindrical shape of a
cylindrical socket or plug but with curving of the contact springs
2, to form a linear contact spring socket 12. For this purpose, a
socket body 13 with an electrical connecting piece 9 is provided
for use with the contact element 1, which body 13 has a slot-like
linear (flat) recess 14. The two metal strips (the bearing piece 3
and the support piece 5), together with the spacing members 6 and
the radially curved contact springs 2, are inserted into the recess
14, with the metal strip forming the bearing piece 3 being inserted
first, and this inserted assembly, comprising a contact spring
structure, is affixed to the body 13. The spacing members 6 abut
the lower wall 15 of the wall pair 15, 16 of flat walls of the
socket body 13, such that the curved contact springs 4 extend
upward into the recess 14. The metal strip which forms the support
piece 5 is disposed near the external opening of the recess 14. To
protect the free ends of the contact springs from contact with an
opposing contact (which is not shown) when the latter is inserted
into the recess 14, the metal strip forming the support piece 5 is
provided with an extension edge 17 positioned in the plane of the
spacing members 6. A holding slot 18 adjoins the flat recess 14.
The metal strip which forms the bearing piece 3 is affixed in this
slot. Advantageously, a known method of spot welding is employed to
affix the extension edge 17 in the flat recess, to the wall 15 of
the socket body 13.
The extension edge 17 in FIG. 4 serves as mentioned hereinabove to
protect the free ends of the contact springs from contact with an
opposing contact. Similar structures, the radially directed guide
edge 19 of FIG. 5, 19' of FIG. 6, and the rounded head 24 of FIG.
8, is provided on the socket body 7 and plug body 11. The guide
edge 19 of FIG. 5 extends over the support piece 5 to protect
it.
While preferred embodiments have been shown and described, the
present invention is not limited thereto, but may be otherwise
embodied within the scope of the following claims.
* * * * *